FIG. 1 is a diagram schematically illustrating the configuration of a prior art remote sensing system. The remote sensing system 200 includes a client apparatus (terminal) C, a server apparatus S installed at a location remote from the client apparatus C, and a public communication network NT which is a digital network or the like for interconnecting these apparatuses via an electrical communication line.
Server apparatus S transmits a sensor control signal for controlling sensors 1 to 3 to client apparatus C which, based on the sensor control signal, controls sensors 1 to 3 to perform the sensing of target objects. Sensor information acquired by sensors 1 to 3 is transmitted from client apparatus C via a public communication network NT to server apparatus S where the information is stored or made available for use.
Patent document 1 mentioned below discloses a sensor information network system in which measurement data acquired by a mobile terminal or a specified measuring device is recorded along with geographic location information of that mobile terminal or measuring device.
On the other hand, patent document 2 mentioned below discloses an account settling apparatus, equipped with a voice response function, that transmits settlement-related information by embedding it in a voice signal in a voice communication between the account settling apparatus and a telephone terminal.
Further, patent document 3 mentioned below discloses a method of embedding supplemental data in a digital phone signal without affecting backward compatibility of the digital phone signal, through transforming the digital voice phone signal into encoded sets of frequency-domain or other transform coefficient representations of the signal.    Patent document 1: Japanese Unexamined Patent Publication No. 2002-351927    Patent document 2: Japanese Unexamined Patent Publication H11-353399    Patent document 1: Japanese Unexamined Patent Publication No. 2003-526274